TUBB4A and neoplasm: Aberrant expression of TubB3, TubB2, TubB4A, TubB4B, and TubB5 isotypes has been detected in several tumor types and is also associated with resistance to tubulin-binding agents, such as taxanes and vinca alkaloids, in different cancer cell types [54,58,59,60,61,62,63,64,65,66]; this may be due to the specific properties of tubulin isoforms which could alter the sensitivity of MTs to this class of drugs.